S3 – Revision Notes and Summer Assignment
The concepts listed below are some of the basics which are essential for the learning of chemistry. All students
taking chemistry in S4 are expected to revise and master them during the summer so as to secure a solid
foundation in chemistry. All these concepts will be assessed in the first week of September.
1.
Classify common elements as metals or non-metals
2.
Write names and chemical symbols for the first 20 elements
3.
Show by means of numbering and electron diagram the electronic arrangements of elements with atomic
numbers 1 to 20
4.
Define period and group of an element in the Periodic Table
5.
Remember the order of the first 20 elements
6.
Recall the period and group to which an element of known atomic number belong
7.
Describe the group trend of group I, II, VII and O.
8.
Understand that metal atoms tend to lose electrons, forming positive ions
9.
Understand that non-metal atoms tend to gain electrons, forming negative ions
10. Understand that ionic bond is formed by complete transfer of electrons
11. State the formulae of common ions (see the table on P.2)
12. Deduce the chemical formulae of ionic compounds.
13. Draw electron diagrams to show the formation of ions
14. Draw electron diagrams of ionic compounds
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Common Ions (*** VERY VERY IMPORTANT ***)
Positive ion (Cation)
Name
Ion of group I
element
Negative Ion (Anion)
formula
potassium ion
K
sodium ion
Na 
Name
Ion of group VII
element
formula
fluoride ion
F
chloride ion
Cl 
bromide ion
Br 
I
iodide ion
Ion of group II
element
magnesium ion
Mg 2
calcium ion
Ca 2
Ion of group III
element
aluminium ion
Al 3



copper (I) ion
Cu 
copper (II) ion
Cu 2
lead (II) ion
Pb 2
Ion of transition
iron (II) ion
metal which forms
more than 1 type iron (III) ion
cobalt (II) ion
of ion
Fe 2
nickel (II) ion
Ni 2
Fe 3
Name of cation:
S
Ion of group V
element
nitride ion
N 3
phosphide ion
P 3
hydroxide ion
OH 
nitrate ion
NO3 
nitrite ion
NO2 
sulphate ion
SO4
Polyatomic anion sulphite ion
SO3








carbonate ion
CO3
hydrogencarbonate ion
HCO3 
permanganate ion
MnO4 
dichromate ion
Cr2O7

Ag 
Ion of transition silver ion
metal which forms zinc ion
only 1 type of ion
non-metal cation
sulphide ion

Co 2
Cr 3
O

2
manganese (II) ion Mn
chromium (III) ion
oxide ion



Ion of group VI
element
Zn 2

hydrogen ion
H
ammonium ion
NH4 
use the name of the element
Note: Some elements can forms more than one type of ions. For example, copper forms Cu+ and
Cu2+ ions. To distinguish them, their names must indicate the charge they carry.
Name of anion:
(i)
For simple ion:
end with “ide”
(ii)
For polyatomic ion:
names depend on the composition of ion
e.g.
containing O, end with “ate” or “ite”. The polyatomic anion with more O is
named as –ate, and that with less O as -ite, e.g. SO4

sulphate, SO3

sulphite.
2
Block: __________ Class: _________ Name: _____________________________
Exercise (To be submitted in the first chemistry lesson after the summer holiday)
1. Give the chemical symbols for the following elements and classify them as metal, non-metal or semi-metal.
a) Oxygen
h) Silicon
b) Calcium
i) Chlorine
c) Sulphur
j) Phosphorous
d) Carbon
k) Beryllium
e) Neon
l) Aluminium
f) Sodium
m) Hydrogen
g) Boron
n) Argon
2. Give TWO examples of elements for each of the following.
a) Group I
e)
b) Group II
f)
c) Group III
g)
d) Group IV
h)
Group V
Group VI
Group VII
Group 0
3. For each of the elements below, state its group number (without referring to Periodic Table).
a) Carbon
k) Nitrogen
b) Fluorine
l) Sodium
c) Magnesium
m) Sulphur
d) Nitrogen
n) Lithium
e) Iodine
o) Calcium
f) Oxygen
p) Silicon
g) Helium
q) Phosphorous
h) Aluminium
r) Chlorine
i) Potassium
s) Argon
j) Boron
4. Give the chemical formula for each of the following ions (without referring to reference materials).
a) Sulphide ion
l) Permanganate ion
b) Calcium ion
m) Dichromate ion
c) Oxide ion
n) Sulphate ion
d) Sodium ion
o) Hydroxide ion
e) Nitride ion
p) Sulphite ion
f) Chloride ion
q) Carbonate ion
g) Magnesium ion
r) Hydrogencarbonate ion
h) Phosphide ion
s) Ammonium ion
i) Fluoride ion
t) Nitrate ion
j) Calcium ion
u) Nitrite ion
k) Potassium ion
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5. State the number of protons, neutrons and electrons for each of the following
Number of protons
a)
81
35𝐵𝑟
b)
81
−
35𝐵𝑟
c)
55
25𝑀𝑛
d)
55
2+
25𝑀𝑛
e)
1 +
1𝐻
f)
127 −
53𝑋
g)
127 +
53𝑌
Number of neutrons
Number of electrons
Steps for drawing electron diagram
1.
2.
State the symbol of the metal and non-metal respectively.
Recall the group to which each belongs, hence work out the number of electrons to be lost or gained to obtain
noble gas electronic structure. Hence, represent the electrons in the outermost shell of the ions using symbols
 and .
3.
State the charge of the ions formed on the top right hand corner.
For metal ion:
positively charged.
For non-metal ion:
4.
negatively charged.
Deduce the ratio of the ions in the formulae so that the total positive charges balance that of negative charges.
4
5. Draw the electron diagrams for each of the following ionic compounds. In all cases, show only the outer-shell
electrons.
Compound
Electron Diagram of Ionic Compound
Chemical formula
a) calcium bromide
b) magnesium oxide
c) aluminium oxide
d) sodium sulphide
e) calcium nitride
5
Steps for Deducing Chemical Formulae of Ionic Compounds using the “Cross Method”
e.g. Give the formula of ionic compound formed by magnesium and chlorine.
Step 1 : State the formulae of the
ions
Step 2: Copy the numerical value of
the charge to the diagonals as
shown as subscripts
Step 3: Rewrite the formula
(i)
with the charge omitted.
(ii)
The subscripts of should
be simplified to simplest
ratio
(iii)
Brackets are only used if
there is more than 1
polyatomic ion in the
formula
Example 1
Magnesium chloride
Mg2+ and Cl-
Mg2+
Example 2
Calcium oxide
Ca2+ and O2-
Cl -
Ca2+
2
2
1
MgCl2
O22Ca2O2
CaO
Example 3
Calcium hydroxide
Ca2+ and OH-
Ca12+
OH- 2
Ca(OH)2
*bracket is needed for
OH- as 2 polyatomic ion
(hydroxide ions)are
involved.
6. Give the chemical formulae of the following ionic compounds
a) Magnesium oxide
m) Calcium nitrate
b) Potassium chloride
n) Sodium hydroxide
c) Aluminium oxide
o) Aluminium sulphate
d) Magnesium bromide
p) Iron (II) hydroxide
e) Calcium nitride
q) Iron (III) oxide
f) Calcium carbonate
r) Copper (II) sulphate
g) Ammonium chloride
s) Lithium oxide
h) Sodium sulphate
t) Calcium chloride
i) Magnesium hydroxide
u) Magnesium sulphate
j) Calcium hydrogencarbonate
v) Potassium dichromate
k) Sodium carbonate
w) Potassium permanganate
l) Ammonium dichromate
x) Sodium sulphite
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